Since this mentions "offline" use and Pro 2.1.1, I'm going to add this into the conversation. I'm not sure if this is 100% related, but just in case the Pro, Pro "offline" and Desktop "borrowing" is a common thread....
I'm trying to use Python 2.7 (Desktop 10.6 in my case) to import arcpy into an external Python IDE with a borrowed Desktop license(from CU license manager) and I am having issues. Seems to work fine if on the network so it can see my concurrent license. I also have Pro 2.1.1 installed.
So, not sure if it is the borrowed license, being offline, Pro 2.1.1 or Desktop 10.6. that might be causing the issue.
(note, I also installed/upgrade to MS Office 365 ...enterprise license.. atlhough I don't think that is the problem).
I have a tech support call in and they are looking into it.
the other geonet thread https://community.esri.com/message/749008-re-arcpy-import-is-really-slow-2-minutes for anyone interested.
Not hijacking this thread, just want to throw this out in case it helps solve both issues.